Electro-optic Display Composite Adhesive Thermal Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Electrophoretic displays face issues with long-term image quality due to particle settling, particularly in gas-based media, which limits their widespread usage, and existing lamination adhesives compromise between low temperature performance and resolution, restricting their application range.

Innovation Solution

Development of composite materials with a polymer phase and a filler phase, where the filler phase has a conductivity greater than or equal to 0.5 × 10^(-3) S/m and a coefficient of thermal expansion ratio less than or equal to 0.5, incorporated in the lamination adhesive to stabilize conductivity across a wide temperature range, reducing particle settling and improving display performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If gas-based electrophoretic media are used, then particle settling occurs more rapidly, but the display can achieve simpler structure and lower cost

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidimage quality stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite materials consisting of electrophoretic particles suspended in a gas-filled porous matrix material. This composite structure prevents particle settling by providing a solid support framework while maintaining the gas-based medium's advantages, thereby resolving the contradiction between manufacturing simplicity and image quality stability.

Inventive Principle:
Principle #40Composite materials

2Temperature

If existing lamination adhesives are used, then low temperature performance is improved, but resolution deteriorates due to compromised application range

Engineering Contradiction:
Improvelow temperature performanceVSAvoiddisplay resolution
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent modifies the physical and chemical parameters of the adhesive material by incorporating it into a composite structure with controlled porosity and thermal properties. This allows the adhesive to maintain flexibility at low temperatures without excessive expansion that would compromise resolution, thus resolving the contradiction between temperature performance and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If filler phase with high conductivity is incorporated in adhesive, then conductivity stability across temperature range is improved, but adhesive complexity increases

Engineering Contradiction:
Improveconductivity stabilityVSAvoidadhesive composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by incorporating conductive filler phases specifically in regions where conductivity stability is critical, such as at the interfaces between electro-optic material layers and conductors. This targeted approach provides conductivity stability without requiring the entire adhesive composition to be complex, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The composite materials enhance the stability of electrophoretic displays by minimizing particle settling and maintaining conductivity consistency across varying temperatures, thereby improving image quality and operational flexibility.

Implementation Method 1

a coefficient of thermal expansion ratio less than or equal to 0.5

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a plurality of charged particles move through a fluid under the influence of an electric field

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Data Source

PatentEP4222556B1Electro-optic display and composite materials having low thermal sensitivity for use therein
Publication Date: 2024.11.20 E INK CORP
  • EP4222556B1 patent drawingFigure 1
  • EP4222556B1 patent drawingFigure 2
  • EP4222556B1 patent drawingFigure 3A~3B

AI summary

An electro-optic display includes a layer of electro-optic material, at least one conductor, and an adhesive material between the layer of electro-optic material and the at least one conductor. At least one of the electro-optic material and adhesive material comprises a composite material that includes a polymer phase and a filler phase, the filler phase having a conductivity greater than or equal to 0.5 X 103 S/m, a ratio of the coefficient of thermal expansion of the filler to the polymer is less than or equal to 0.5, and a concentration of the filler phase in the composite material is greater than or equal to a filler concentration corresponding to a conductivity transition point of the composite material